1. Field of the Invention
The present invention relates to an electrostatic image forming apparatus, usable in a printer, facsimile or digital copying machine.
2. Description of the Related Art
In an optical printer or a digital copying machine, after uniformly charging a photosensitive body having a photoconductive characteristic, the exposure of the portion to be visible is done by radiating light rays, and thereby an electrostatic latent image is formed thereon.
The electrostatic latent image is developed by toner charged with a polarity which is the same as that of the photosensitive body. A visible image obtained in such a manner is electrostatically transferred onto transfer paper.
The toner for forming the visible image on the photosensitive body is not always entirely transferred onto the transfer paper. Even after transferring the visible image onto the recording paper, a considerable amount of toner remains on the photoconductive body. In such a situation, it may be necessary to perform cleaning of the toner remaining on the photosensitive body such that the remaining toner does not have any effect on the subsequent image forming process.
An electrostatic fur brush method has ben well known as a cleaning method. In this method, cleaning is done in such a manner that toner is electrostatically captured by the fur brush.
At the time of electrostatic transferring, the toner creating the visible image formed on the photosensitive body is exposed to a corona discharge of inverse polarity to that of charge at the time of developing.
Until now, there remained a considerable amount of toner inversely charged to the polarity of the remaining toner.
The amount of charge in the respective remaining toner is not constant. Generally, the distribution of the charge amount forms a peak on a distribution graph.
Until now, there remained a problem that it was difficult to increase the cleaning efficiency by using the electrostatic fur brush method, in view of the distribution of the charge amount in the remaining toner.